The bladder is a hollow organ in the lower pelvis. Its main job is to store urine, and its flexible, muscular walls are lined with urothelial cells. Bladder cancer begins when healthy cells change and grow out of control, forming a tumor. Cancer that develops in the renal pelvis and ureters is also considered a type of bladder cancer and is often called upper tract bladder cancer.
Forms of bladder cancer
Urothelial carcinoma (UCC) accounts for about 90 percent of all bladder cancers. UCC is sometimes also called transitional cell carcinoma or TCC.
Squamous cell carcinoma can develop in the bladder lining from irritation and inflammation and is almost always invasive.
Adenocarcinoma develops from glandular cells and is almost always invasive.
Small cell carcinoma accounts for less than one percent of bladder cancers. It develops in neuroendocrine cells and often grows quickly.
Sarcomas are very rare and start in the muscle cells of the bladder.
Risk factors for bladder cancer
Smoking — The most important risk factor for bladder cancer, smoking causes about half of all cases in both men and women. Bladder cancer is at least three times as likely to occur in smokers compared to non-smokers.
Age — Bladder cancer risk increases with age. More than 70 percent of people with bladder cancer are older than 65.
Gender — Men are four times more likely to develop bladder cancer than women, but women are more likely to die from bladder cancer than men.
Race and ethnicity — Whites are about twice as likely to develop bladder cancer as African Americans and Hispanics. However, African Americans are twice as likely to die from the disease. Asian Americans and Native Americans have slightly lower rates of bladder cancer.
Chemicals — Chemicals used in the textile, rubber, leather, dye, paint, and print industries; some naturally occurring chemicals; and chemicals called aromatic amines can increase the risk of bladder cancer. The risk becomes especially high when people exposed to these chemicals are also smokers.
Chronic (ongoing) bladder irritation and infections — Urinary infections, kidney and bladder stones, bladder catheters left in place a long time, and other causes of chronic bladder irritation have been linked to bladder cancer. Schistosomiasis (also called bilharziasis), an infection with a parasitic worm that can get into the bladder, is also a risk factor for bladder cancer. This is an extremely rare cause of bladder cancer in the United States.
Cyclophosphamide — People who have had chemotherapy with cyclophosphamide (Cytoxan®) have a higher risk of developing bladder cancer because this drug can irritate the bladder. For that reason, people taking this drug are often told to drink plenty of fluids.
Radiation — People who are treated with radiation to the pelvis are more likely to develop bladder cancer.
Pioglitazone — According to the US Food and Drug Administration (FDA), use of the diabetes medicine pioglitazone (Actos®) is linked with an increased risk of bladder cancer. The risk seems greater when higher doses are used.
Arsenic — When found in drinking water, arsenic has been associated with an increased risk of bladder cancer. The chance of being exposed to arsenic depends on where you live and whether you get your water from a well or from a system that meets the standards for acceptable arsenic levels.
Dietary Supplements — Supplements containing aristolochic acid (mainly in herbs from the Aristolochia family) have been linked with an increased risk of urothelial cancers, including bladder cancer.
Not drinking enough fluids — Lower hydration means the bladder is emptied less often. People who drink fluids less often tend to have higher rates of bladder cancer than people who drink a lot of fluids each day, especially water.
Personal history of bladder or other urothelial cancer — Having cancer in the lining of any part of the urinary tract puts you at higher risk of having another cancer, either in the same spot as before, or in another part of the urinary tract.
Family history — People who have family members with bladder cancer have a higher risk of getting it themselves, through similar risk exposures (like tobacco) and/or inherited gene changes (like those linked to Cowden disease and Lynch syndrome).
Bladder birth defects — Rare birth defects associated with bladder cancer include an incomplete separation of the belly button and the bladder (where cancer develops in their connection, called the urachus), and bladder exstrophy, in which both the bladder and the abdominal wall in front of the bladder don’t close completely during fetal development and are fused together.
Symptoms of bladder cancer
Blood in the urine
Needing to urinate many times during the night
Pain or burning during urination
Feeling the need to urinate even when your bladder isn’t full
Having trouble urinating or having a weak urine stream
Symptoms of advanced bladder cancer
Being unable to urinate
Lower back pain on one side
Loss of appetite and weight loss
Feeling tired or weak
Swelling in the feet
How is bladder cancer treated with radiation?
External-beam radiation therapy (EBRT), delivered from outside the body, is the type of radiation therapy used most often to treat bladder cancer. Radiation therapy is often given along with chemotherapy.
Radiation may be used as the main treatment for people with earlier-stage cancers who can’t have surgery or chemotherapy.
Radiation may be used to try to avoid cystectomy (surgery to remove the bladder).
Radiation may be used after surgery (and with chemotherapy) to destroy any remaining cancer cells, so all or part of the bladder does not have to be removed.
Radiation may be used to treat a metastasis located in one area, such as the brain or bone.
Radiation may be used as palliative therapy to relieve symptoms caused by a tumor, such as pain, bleeding, or blockage.
More extensive information about bladder and other cancers may be found at these sites:
American Cancer Society: Cancer.org
American Society of Clinical Oncology: Cancer.net
National Cancer Institute: Cancer.gov